A related-art refrigeration cycle apparatus provided with an ejector is configured to suppress decreasing an evaporation capacity and an operating efficiency by lowering a refrigerant flow rate into an evaporator due to a shortage of a driving power of the ejector (see Patent Literature 1, for example).
The related-art device includes a check valve bridge circuit for using the ejector in both a cooling operation and a heating operation. Further, a bypass circuit for bypassing the check valve bridge circuit connects a high-pressure-side inlet to a low-pressure-side outlet of the check valve bridge circuit with a refrigerant pipe and a bypass valve. A refrigerant circuit is formed such that when the evaporation capacity and the efficiency of the refrigeration cycle decrease due to the shortage of the recovery power in the ejector, this bypass circuit opens the bypass valve and fully closes a valve of a nozzle in the ejector so as to reduce a pressure using a regular expansion valve without using the ejector.
With this configuration, the refrigeration cycle apparatus can perform a high-efficiency operation due to power recovery of the ejector and provide high reliability due to a provision of the bypass circuit. Also, since the high-temperature heat source on the load side can be used during a defrosting operation, it is possible to reduce the time required for the defrosting operation. Thus, the suspension time of a heating operation is reduced, which makes it possible to prevent a reduction in comfort.
Further, with regard to refrigeration cycle apparatuses that provide improved heating capacity using a compressor having an injection port, a refrigeration cycle apparatus is known that has a configuration in which an outlet-side pipe of a condenser is connected to an injection port through a throttle mechanism and an internal heat exchanger by piping, for example. With this configuration, the throttle mechanism controls the injection flow rate. Further, in order to prevent liquid injection into a compressor, a refrigerant having a high dryness due to heat exchange by the internal heat exchanger is injected. Thus, it is possible to improve the reliability of the compressor (see Patent Literature 2, for example).